4wd or winter tyres, which is better?
Discussion
I posted this in the winter tyres thread, but some of you may have not seen it, so I'll post it here.
This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
300bhp/ton said:
Looked like it stopped fine to me and demonstrates how good non winter narrow MT's are in such conditions. Sometimes you want a bit of lock up in a harder stop, as opposed to just slowing. Fresh snow can (depends on the snow) act very similar to sand or gravel. Locking up allows the tyre blocks to dig in and build up snow in front of the tyres. All helping to slow you down.
You are delusional if you think sliding sideways towards another vehicle when stopping from 15mph is a good thing and somehow proof of 4WD's advantages.Any winter tyre equipped vehicle would've stopped without drama in that situation. No sliding, no need to build up snow in front of the tyres, no ABS involvement, no need for AWD.
jagnet said:
You are delusional if you think sliding sideways towards another vehicle when stopping from 15mph is a good thing and somehow proof of 4WD's advantages.
Any winter tyre equipped vehicle would've stopped without drama in that situation. No sliding, no need to build up snow in front of the tyres, no ABS involvement, no need for AWD.
This Any winter tyre equipped vehicle would've stopped without drama in that situation. No sliding, no need to build up snow in front of the tyres, no ABS involvement, no need for AWD.
jagnet said:
You are delusional if you think sliding sideways towards another vehicle when stopping from 15mph is a good thing and somehow proof of 4WD's advantages.
Any winter tyre equipped vehicle would've stopped without drama in that situation. No sliding, no need to build up snow in front of the tyres, no ABS involvement, no need for AWD.
Maybe you should try providing some actual evidence and first hand accounts then? You seem rather light on substance, yet quick and willing to hand out derogatory insults.Any winter tyre equipped vehicle would've stopped without drama in that situation. No sliding, no need to build up snow in front of the tyres, no ABS involvement, no need for AWD.
300bhp/ton said:
I posted this in the winter tyres thread, but some of you may have not seen it, so I'll post it here.
This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
Thanks for the link 300bhp. This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
His explanation was that the brake bias is different when he engages four wheel drive. I don't understand why that would be. Brake proportioning valves on road cars are usually dependant on brake pressure and the amount of load in the car. Not which wheels are being driven. It's how they determine whether it is just Kylie driving in her undies, or four prop forwards with a boot full of bricks. Can anyone technical explain why would brake bias differ when he engages four wheel drive over rear wheel drive?
You say his explanation is why it works with engine braking too. Engine braking has nothing to do with brake bias, so I am further confused but ready for someone to explain it please.
300bhp/ton said:
Maybe you should try providing some actual evidence and first hand accounts then? You seem rather light on substance, yet quick and willing to hand out derogatory insults.
I live up in the Nordic region and have driven all sorts of 2wd and 4wd cars with or without winter tyres, winter tyres are a must on snow and ice, nothing beats them for stopping power and steering response, simple as that. This is backed up by pretty much every tyre manufacturer, car manufacturer, car journalist and everyone who has tried winter tyres in winter conditions, not to mention the legislation in many countries where snow is an everyday thing during the year.
RicksAlfas said:
Thanks for the link 300bhp.
His explanation was that the brake bias is different when he engages four wheel drive. I don't understand why that would be. Brake proportioning valves on road cars are usually dependant on brake pressure and the amount of load in the car. Not which wheels are being driven. It's how they determine whether it is just Kylie driving in her undies, or four prop forwards with a boot full of bricks. Can anyone technical explain why would brake bias differ when he engages four wheel drive over rear wheel drive?
You say his explanation is why it works with engine braking too. Engine braking has nothing to do with brake bias, so I am further confused but ready for someone to explain it please.
Hi, I put an explanation in the Winter Tyres thread.His explanation was that the brake bias is different when he engages four wheel drive. I don't understand why that would be. Brake proportioning valves on road cars are usually dependant on brake pressure and the amount of load in the car. Not which wheels are being driven. It's how they determine whether it is just Kylie driving in her undies, or four prop forwards with a boot full of bricks. Can anyone technical explain why would brake bias differ when he engages four wheel drive over rear wheel drive?
You say his explanation is why it works with engine braking too. Engine braking has nothing to do with brake bias, so I am further confused but ready for someone to explain it please.
I'm more enthusiast than outright engineer, so this is my take on it. But I'm reasonably certain I'm on the right track.
300bhp/ton said:
Normal road cars normally have a brake bias with 70+% to the front. Because on grippy tarmac when you brake you get a lot of weight transfer to the front. In slippery conditions you will not get the same weight transfer, as you won't generate enough grip on the front wheels. The aim of the heavy front bias is simple, under hard braking you want all the wheels to lock up at about the same time, the fronts slightly before the rears. Due to the weight transfer under braking, the fronts need to work a lot hard to lock the tyres up/induce ABS.
You can see how much the nose dives under braking, even on a car with stiff suspension:
But the heavy front brake bias means, when on a slippery surface that the front wheels will lock up/induce ABS much sooner and earlier on with a lot less braking effort. This is simply because you aren't getting the weight transfer on a slippery surface. When this happens it will reduce your rear braking effort, especially if equipped with ABS, where it will kick the ABS in and further reduce braking forces. The rear brakes are being highly under utilised, as you never get to brake hard enough to make them work to their full extent in these conditions. And the crux is, the rears probably won't be at the point of lock up or inducing the ABS under these conditions, meaning they could have helped brake and slow you more so.
On a slippery surface you want a more even front to rear brake bias (nearer to 50:50), so that all the wheels want to lock at the same time (50:50 bias would be bad on a dry tarmac roads, as the weight transfer under braking to the front on grippy surfaces would make the rears lock up before the fronts, causing you to spin). Hence why there is a front bias for the brakes as standard.
By locking the front and rear props together with a 4wd system (and centre diff lock if equipped). It effectively means that the rear wheels will have the same brake bias as the fronts, as some braking will be coming from the prop, which directly joins the front and rear axles together.
The end result on a slippery surface is a vehicle able to apply more braking force in total before lockup and less chance of kicking in the ABS. Hence why it will stop quicker (shorter distance). As demonstrated repeatedly in the video.
Cars with open centre differentials such as late model Jaguar X-Types will see no benefit at all, as the front and rear axles aren't directly joined or turning at the same speed. A Land Rover Defender with the centre diff lock open would also not benefit, but it would when the centre diff lock is engaged.
Limited slip centre diffs will see some benefit, but not as much as a directly linked setup.
You can see how much the nose dives under braking, even on a car with stiff suspension:
But the heavy front brake bias means, when on a slippery surface that the front wheels will lock up/induce ABS much sooner and earlier on with a lot less braking effort. This is simply because you aren't getting the weight transfer on a slippery surface. When this happens it will reduce your rear braking effort, especially if equipped with ABS, where it will kick the ABS in and further reduce braking forces. The rear brakes are being highly under utilised, as you never get to brake hard enough to make them work to their full extent in these conditions. And the crux is, the rears probably won't be at the point of lock up or inducing the ABS under these conditions, meaning they could have helped brake and slow you more so.
On a slippery surface you want a more even front to rear brake bias (nearer to 50:50), so that all the wheels want to lock at the same time (50:50 bias would be bad on a dry tarmac roads, as the weight transfer under braking to the front on grippy surfaces would make the rears lock up before the fronts, causing you to spin). Hence why there is a front bias for the brakes as standard.
By locking the front and rear props together with a 4wd system (and centre diff lock if equipped). It effectively means that the rear wheels will have the same brake bias as the fronts, as some braking will be coming from the prop, which directly joins the front and rear axles together.
The end result on a slippery surface is a vehicle able to apply more braking force in total before lockup and less chance of kicking in the ABS. Hence why it will stop quicker (shorter distance). As demonstrated repeatedly in the video.
Cars with open centre differentials such as late model Jaguar X-Types will see no benefit at all, as the front and rear axles aren't directly joined or turning at the same speed. A Land Rover Defender with the centre diff lock open would also not benefit, but it would when the centre diff lock is engaged.
Limited slip centre diffs will see some benefit, but not as much as a directly linked setup.
300bhp/ton said:
I posted this in the winter tyres thread, but some of you may have not seen it, so I'll post it here.
This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
Unless you drive a pick-up with a transfer case and an archaic abs system with shot/seized rear brakes, this vid is totally irrelevant. Any well controlled rear braking system will easily provide all the braking retardation the grip at offer can provide. This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
Engine braking is also totally irrelevant for safe braking, unless you are going 90 degrees sideways and coming off the trottle at that point... At which point most people will disagree that your driving style is anywhere near 'safe'...
As I wrote somewhere before on this forum, actually 4wd is a risk factor as you will gather speed quicker and will notice a reduced grip situation much later, given that braking grip is naught better 99, 9987% of the time. With the same reasoning, rwd and summer tyres are by far the best, as on snow you won't be able to leave your driveway and won't be able to crash at any significant speed. Unless you glide out uncontrollable onto the lower lying street and someone comes driving on the 4wd summer tyred car at about the same time...
Onehp said:
...on snow?
Winter tyres of course.
If anybody claims differently, or just thinks they are somehow 'safe' with their 4wd on summers, let them watch this straightforward comparison:
Tyrereviews 2wd winter vs 4wd summer
On wet roads, they are roughly the same, on dry cold roads, the summers may be a bit better. And on acceleration 4wd is always better in the dry/wet, but only relevant if you need to win dragraces.... But once the white stuff comes falling down summers don't have a chance. At all.
PS: for those in the nordic countries: put descent nordic winter tyres on your 4wd cars instead of all seasons 21" tyres whatever. The difference is just as large as above especially on ice...
Regards,
Onehp from Sweden
PSS in summer, Icecontact 2 studded (190 studs/tyre) in winter.
That's a pretty conclusive video.Winter tyres of course.
If anybody claims differently, or just thinks they are somehow 'safe' with their 4wd on summers, let them watch this straightforward comparison:
Tyrereviews 2wd winter vs 4wd summer
On wet roads, they are roughly the same, on dry cold roads, the summers may be a bit better. And on acceleration 4wd is always better in the dry/wet, but only relevant if you need to win dragraces.... But once the white stuff comes falling down summers don't have a chance. At all.
PS: for those in the nordic countries: put descent nordic winter tyres on your 4wd cars instead of all seasons 21" tyres whatever. The difference is just as large as above especially on ice...
Regards,
Onehp from Sweden
PSS in summer, Icecontact 2 studded (190 studs/tyre) in winter.
Onehp said:
300bhp/ton said:
I posted this in the winter tyres thread, but some of you may have not seen it, so I'll post it here.
This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
Unless you drive a pick-up with a transfer case and an archaic abs system with shot/seized rear brakes, this vid is totally irrelevant. Any well controlled rear braking system will easily provide all the braking retardation the grip at offer can provide. This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
Engine braking is also totally irrelevant for safe braking, unless you are going 90 degrees sideways and coming off the trottle at that point... At which point most people will disagree that your driving style is anywhere near 'safe'...
As I wrote somewhere before on this forum, actually 4wd is a risk factor as you will gather speed quicker and will notice a reduced grip situation much later, given that braking grip is naught better 99, 9987% of the time. With the same reasoning, rwd and summer tyres are by far the best, as on snow you won't be able to leave your driveway and won't be able to crash at any significant speed. Unless you glide out uncontrollable onto the lower lying street and someone comes driving on the 4wd summer tyred car at about the same time...
Your last paragraph
300bhp/ton said:
Maybe you should try providing some actual evidence and first hand accounts then? You seem rather light on substance, yet quick and willing to hand out derogatory insults.
You want video evidence of a 2wd car on winter tyres managing to brake to a standstill in snow, without drama, from 15mph? How about this: https://youtu.be/hy3FUOHP434 downhill on a ski slope. Tiny bit of abs at one point just before coming to a stop but forgiveable as it's a frelling ski slope! A little tougher than conditions in your video but no need for diff locks, engine braking on the rear axle etc etc.
Plenty of other videos of 2wd cars managing to do the same on YouTube.
What other evidence would you like? That anyone living in Sweden, Norway, Germany, Austria, Poland, Czech Republic, Slovakia etc etc manage it every day in winter when it snows? They're not heading out in their defenders, engaging diff locks and filming themselves trundling about at 15mph, they're just getting in their cars and driving to work like it's any another day.
Paddy_N_Murphy said:
Finlandia said:
I live up in the Nordic region and have driven all sorts of 2wd and 4wd cars with or without winter tyres, winter tyres are a must on snow and ice, nothing beats them for stopping power and steering response, simple as that.
This is backed up by pretty much every tyre manufacturer, car manufacturer, car journalist and everyone who has tried winter tyres in winter conditions, not to mention the legislation in many countries where snow is an everyday thing during the year.
Yea, but other than that.... what makes you think that the lone figure (sliding sideways down the road) doesn't have more knowledge than those combined ?This is backed up by pretty much every tyre manufacturer, car manufacturer, car journalist and everyone who has tried winter tyres in winter conditions, not to mention the legislation in many countries where snow is an everyday thing during the year.
PorkInsider said:
Digga said:
That's a pretty conclusive video.
Very much so but in the (paraphrased) words of Michael Gove, “some people on PH have had enough of experts”They will not be convinced that 4WD on summers is chocolate fireguard territory, when it comes to wintry conditions.
I've never bothered with the expense or hassle of winter tyres and here in the UK that decision has never really come back to haunt me tbh.
I'm sure a winter tyre is better in winter conditions just like a knife is better for spreading butter than a fork!! But how many days of the year would you really, truly need them in this country??
The roads in the UK are treated so stick to them. Anyway if the road is so bad and people are stuck. So are you. No matter what tyre you have. You can't drive over other vehicles.
I'm sure a winter tyre is better in winter conditions just like a knife is better for spreading butter than a fork!! But how many days of the year would you really, truly need them in this country??
The roads in the UK are treated so stick to them. Anyway if the road is so bad and people are stuck. So are you. No matter what tyre you have. You can't drive over other vehicles.
Finlandia said:
I live up in the Nordic region and have driven all sorts of 2wd and 4wd cars with or without winter tyres, winter tyres are a must on snow and ice, nothing beats them for stopping power and steering response, simple as that.
This is backed up by pretty much every tyre manufacturer, car manufacturer, car journalist and everyone who has tried winter tyres in winter conditions, not to mention the legislation in many countries where snow is an everyday thing during the year.
Have I ever climed any different? Stop arguing something that isn't in debate. This is backed up by pretty much every tyre manufacturer, car manufacturer, car journalist and everyone who has tried winter tyres in winter conditions, not to mention the legislation in many countries where snow is an everyday thing during the year.
300bhp/ton said:
Finlandia said:
I live up in the Nordic region and have driven all sorts of 2wd and 4wd cars with or without winter tyres, winter tyres are a must on snow and ice, nothing beats them for stopping power and steering response, simple as that.
This is backed up by pretty much every tyre manufacturer, car manufacturer, car journalist and everyone who has tried winter tyres in winter conditions, not to mention the legislation in many countries where snow is an everyday thing during the year.
Have I ever climed any different? Stop arguing something that isn't in debate. This is backed up by pretty much every tyre manufacturer, car manufacturer, car journalist and everyone who has tried winter tyres in winter conditions, not to mention the legislation in many countries where snow is an everyday thing during the year.
RicksAlfas said:
300bhp/ton said:
I posted this in the winter tyres thread, but some of you may have not seen it, so I'll post it here.
This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
Thanks for the link 300bhp. This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
His explanation was that the brake bias is different when he engages four wheel drive. I don't understand why that would be. Brake proportioning valves on road cars are usually dependant on brake pressure and the amount of load in the car. Not which wheels are being driven. It's how they determine whether it is just Kylie driving in her undies, or four prop forwards with a boot full of bricks. Can anyone technical explain why would brake bias differ when he engages four wheel drive over rear wheel drive?
You say his explanation is why it works with engine braking too. Engine braking has nothing to do with brake bias, so I am further confused but ready for someone to explain it please.
End of discussion far as I'm concerned.
Edited by xjay1337 on Monday 19th November 17:05
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